Kerry Rudolph, a Detroit Water & Sewerage Department supervisor, gazes at the waters of Conner Creek near the city's sewerage plant on the east side. / John Gallagher/Detroit Free Press

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Detroit Free Press Business Writer

MOSES HARRIS/DETROIT FREE PRESS

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Heavy overnight rains prompted the Detroit Water & Sewerage Department’s Conner Creek facility on the city’s east side to spring to action early Wednesday.

As the deluge swamped sewers — mixing rainwater with raw sewage — complicated machinery filtered fecal matter and street debris, from candy wrappers to condoms. A team of technicians disinfected the water with bleach, and then discharged the millions of gallons into the Detroit River.

Overflow facilities like Conner are part of the department’s vast network of pipes, pumps, filters and treatment plants that serve millions in southeast Michigan and cost taxpayers billions of dollars to build and operate. Keeping the river waters safe is an expensive task.

But instead of spending for future facilities, there’s renewed interest across the nation to solve the problem by keeping stormwater out of sewers in the first place through natural means known collectively as “blue infrastructure.”

As it might exist one day in Detroit, the blue solution would involve a network of retention ponds, rainwater gardens and similar sites to help hold or channel stormwater overflows until the water can be absorbed into flood plains and other natural features.

It’s a key goal of the landmark Detroit Future City plan. Released earlier this year, it’s a comprehensive roadmap for revitalizing the city over 50 years, in part by putting increasingly vacant land to productive, environmentally friendly use. There’s a companion “green” infrastructure plan in the report — the idea of using reforestation, urban farms, and other “landscape” types to make Detroit a more environmentally sustainable place.

“We pave roads and we develop sites and that creates more water runoff, and then that water runoff has to go somewhere,” said Sue McCormick, director of the city’s Water & Sewerage Department and a proponent of using more natural solutions to deal with heavy rains.

McCormick said it would cost another $1 billion to adequately deal with the problem through the traditional “big pipe” way. But with suburban customers rebelling against high water rates and Wall Street bond rating agencies downgrading the city’s water department debt this month to “junk” status, the option may be increasingly limited.

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Designing with nature

Like many of the goals in Detroit Future City’s nearly 350-page report, blue infrastructure won’t happen without a massive commitment from the city and the public. There is, for example, no cost estimate or comprehensive plan of action.

Joan Nassauer, a University of Michigan professor of landscape architecture and an expert on blue infrastructure, cautions that even a simple rainwater garden must be properly designed to capture stormwater without creating other problems, such as flooding or mosquito breeding grounds.

“It’s infrastructure. It’s not restoring nature,” Nassauer said. “It should be thought of as constructing eco-system services that employ elements of nature. When you realize it’s a design challenge, then you see the opportunities to design it so that it’s a desirable place to live, which is really what it all comes down to.”

Ironically, Detroit, a national symbol of urban distress, may be the city best positioned to take advantage of 21st-Century blue infrastructure ideas. The city’s vast amount of vacant land — variously estimated at 20 to 40 square miles depending how one counts abandoned parks and closed-off roads — provides needed space to put blue and green solutions into action.

Detroit Future City envisions that over the next 50 years perhaps a third of the city’s 139 square miles could be devoted to the carefully designed projects. That would mean parcels totaling roughly the area of Paris would be devoted to new landscape and natural systems in Detroit, rather than to homes, roads, sidewalks, and commercial activity.

U-M’s Nassauer cautions that the end product will need to be more green — trees, urban farms, and the like — than blue — ponds and lakes. Too many surface water features can lead to problems, including mosquitoes, child safety, aesthetics, and other issues, she said.

“It would be very misleading to envision this as a chain of lakes or some such thing,” Nassauer said. “In my view, the vision might more precisely be described as green infrastructure with the occasional drop of blue. I guess I think you want to be very careful how much blue you have and where you have it.”

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Green solutions

With that in mind, the city’s Water & Sewerage Department has teamed with the non-profit Greening of Detroit in a few small tree-planting pilot projects.

In June, McCormick and Greening of Detroit workers planted trees on several vacant lots in and around the Cody-Rouge district on Detroit’s west side.

Dean Hay, director of green infrastructure for the Greening of Detroit, said restoring the city’s tree canopy would help keep rainwater out of sewers in several ways. Among those: Tree roots loosen the soil so rainwater can infiltrate the ground more easily. Tree trunks and leaves also capture water and hold it until it evaporates.

“Right now we’re at the beginning of the education phase,” Hay said. “There’s a lot of people that may not understand the need for it ... Once we go in and start to talk with people and ask them if they understand where the water goes and we talk with them about how much it costs now to treat that water, it starts to change the paradigm a little bit.”